Carburetor for powdered coal



Decfl,` 1928..

v O. A. KREUTZBERG CARBURETOR FOR PowDERED coAL Filed Feb. 20, 1924 u uum Patented Dec. i 18, 1928.

UNITED STATES OTT A. KBEUTZBERG, 0F LAKE BLUFF, ILLINOIS.

CARBURETOB FOR POWDERED COL.

Application filed February 20, 1924. Serial No. 694,005.

The purpose of this invention is to pro vide improved means for mixingair and powdered fuel such as powdered coal for immediate use in aheating furnace or kunder a power boiler and susceptible of regulationthrough fairly wide limits for varying the intensity of the fire and theheat given off thereby. It consists. of certain features and elements incombination as herein shown and describe-d and as 'indicated by theclaims.

In the drawings Figure l is a front elevation partly in section asindicated at line 1--1 on Figure 2, illustrating a coal carburetingmachine embodying this invention.

Figure 2 is a side elevation showing the coal feed hopper in section.

Figure 3 is a top plan view wit-h the fuel feeding mechanism removedfrom the feed chamber.

In preparing powdered fuel such as finely pulverized coal for combustionthere is of course an ideal proportion preferably to be maintainedbetween the quantity of fuel and the quantity of air furnished for itscombustion. Obviously any considerable excess of air over that requiredfor complete combustion will tend merely to absorb heat units and carrythem off through the stack while insufcient air will produce a smokyflame and will either encrust the entire combustion chamber with soot orcause combustible carbon to be carried away in the smoke. In variousplants the proportion of air supplied with the fuel and that suppliedthrough the draft doors may be varied according to local conditions butin any plant it is desirable to furnish a considerable proportion of theair already mixed with the pulverized fuel.

The apparaus of this invention is designed to do this and since thevolumetricV output of a blower varies quite uniformlyvwith its Speedthrough a considerable range, it is found that by mechanicallyconnecting the fuel feeding` device to the blower so that a certainquantity of powdered fuel isreleased for each revolution of the blowerrotor, a practically constant mixture of air and fuel can be maintainedthrough a considerable rr nge of speeds.

As shown in the drawings, the blower is housed in a casing, 1,surmounted by a feed chamber, 2, which may be understood as beinglocated directly below a storage hopper for powdered fuel indicated indot-ted lines at 3. The blower sha-ft, 4, carrying the blast wheel, 5,is connected Idirectlyto a drive motor, 6, whose speed may be varied inany desired manner; preferably the motor is ofV a variable speed typedesigned for eihcient operation throughout a considerable range ofspeeds. l.Vithin the feed chamber', 2, a

port in the lower part of the chamber, 2, giv- `ing access directly tothe blower casing, 1,

at its upper portion while the dischargev mouth, 14. of the blower isshown at the lower portion of the casing and yat the same side of theshaft, 4. As the blades, 15, of the wheel, 5, rotate from the outlet, 8,to the discharge mouth, 14, it results that the powdered fuel admittedat the outlet, 8, is picked up by the fan blades, 15, and carriedthroughalmost a complete revolution of the wheel, 5, in the directionindicated by arrow X on Figure 2, before arriving at the dischargemouth` 14, thus affording ample opportunity for inter# mixture 'of thepowdered coal with theair handled by the blast wheel. Though the fuelfalls by gravity from the chamber, 2, into the path of the blades, 15,it will be widely dispersed through the air current by centrifugal forceso that substantially allthe fuelV will be discharged from the fan wheelduring the first revolution and will pass with the air to the combustionchamber of the furnace.

To agitar-e the powdered material in the hopper, 2, just sufliciently toprevent it from packing or clogging therein I provide a cagelikestructure comprising two disks, 16, carried on. an axle, 17, andconnected in spaced relation by tie rods, 18. The peripheral portion ofeach disk, 16, is notched and the material cut from the notches isfolded up to form blades, 19, radially arranged. These blade portions ofthe disks, 16, laterally overlap the feeder wheel, 7, anda stud, 20,projecting from one face of saidwheel engages any one of the notchesbetween the blades, 19, so that with each rotation of the feed wheel, 7,the agitator is advanced a. few degrees about its axis Vso as to breakup any packing of the fuel mass in the chamber, 2. As the feed wheel, 7,rotates in the chamber, 2, its outwardly open pockets will till withpowdered fuel and as these pockets pass the discharge port, 8, they willempty `their loads into the blower. However, the angular cxtent of eachpocket is something less than the thickness of the bottoni wall ot thechamber, 2, which the pocket traverses in approaching the port, 8, orleaving it; thus there is always at least one side of one pocketinterposed between the feed chamber, 2, and the edge of the port, 8, sothat the feeder wheel constitutes a complete closure for the port and nopowdered fuel is permitted to leak past the wheel at any positionthereof.

I claim:

l. In an apparatus for mixing powdered fuel and air, an air blast wheeland a casing therefor having a tangential discharge mouth, a feed hopperfor the fuel mounted adjacent the blast wheel casing and formed with anoutlet positioned to direct the fuel toward the periphery of the blastWheel, and means for positively controlling the feed of fuel from thehopper in lixed relation to the .speed of the blast wheel.

2. In an apparatus ior mixing powdered fuel and air,v a centrifugalblast wheel and a casing therefor, a feed hopper for the `l'uel havingan outlet leading into the casing zulyjacent the periphery ofthe blastwheel and measured quantities of the vpowdered fuel to the outlet infixed relation to the speed of the blast Wheel.

OTTO A. KREUTZBERG.

